1. Field of the Invention
The present invention relates to a method of manufacturing products, particularly golf balls, including a blend of highly neutralized acid polymers and an ionomer-based masterbatch containing additives, and to a method for making the blend. The invention also relates to a golf ball including a blend of highly neutralized acid polymers with additives in an ionomer-based masterbatch.
2. Description of Related Art
Golf balls are important sporting goods that have changed with changes in technology. For example, balls were first made of wood, and then by stuffing boiled, softened feathers into a leather sack. The sack typically was painted white, and would tighten upon drying. However, because the feather ball tended to absorb moisture and to split, many balls were required to play a round. Also, these feather balls were expensive as compared with wooden balls.
Both feather and wooden balls were in use until the gutta percha ball was made. The gutta percha ball was relatively inexpensive and easily manufactured. Also, the gutta percha ball was fairly durable, as compared with the feather ball, performed well because the surface could easily be roughened to improve flight characteristics, and so became popular. However, the ball exhibited a tendency to break up in flight.
Golf balls comprising other elastic materials then were developed. For example, a golf ball having a rubber core and an elastic thread wound tightly around the core was developed. The winding was covered with gutta percha at first, but later with balata. However, balata-covered golf balls often are damaged by players who are less skilled at striking the ball. Thus, tougher covers were developed, including in particular covers comprising a Surlyn® compound or a polyurethane compound.
The interior structure of the golf ball also has advanced, with plastics and polymeric materials having properties and characteristics appropriate for manufacture of high-quality, high-performance, affordable golf balls. In particular, polymeric materials having properties and characteristics appropriate for golf ball manufacture have been developed. Such polymeric materials include polyurethanes and ionomeric materials, including highly neutralized acid polymers. Blended materials also are used to manufacture other products.
Blends of materials polymeric often contain other compositions, typically called additives, that adjust properties and characteristics of golf balls and other products to achieve properties and characteristics that may not be available from a single material or from the polymers alone. However, many material blends that manufacturers seek to make are difficult, if not impossible, to make successfully because the components are not compatible or are not easily combined. In particular, highly neutralized acid polymers typically are difficult to blend, and some additives do not blend easily with highly neutralized acid polymers.
Therefore, there exists a need for a method of manufacturing products, particularly golf balls, including a blend of highly neutralized acid polymers and additives that are difficult to combine with highly neutralized acid polymers, and for a method for blending highly neutralized acid polymers with such additives.